Liquid optical brightening concentrate



United States Patent lice.

3,360,479 LIQUID OPTICAL BRIGHTENIN CONCENTRATE Heinrich Hausermann, Riehen, near Basel, Switzerland, assignor to J. R. Geigy A.G., Basel, Switzerland No Drawing. Continuation of application er. No. 419,567, Dec. 18, 1964. This application Dec. 16, 1966, Ser. No. 602,411 Claims priority, application Switzerland, Nov. 20, 1959, 80,847/59 6 Claims. (Cl. 252-3012) This application is a continuation of application Ser. No. 419,567 filed Dec. 18, 1964, now abandoned which in turn is a continuation-in-part of my co-pending application Ser. No. 243,641 filed Dec. 10, 1962, now abandoned, which is in turn a division of co-pending application Ser. No. 70,124 filed Nov. 18, 1960, and which was forfeited.

The invention concerns liquid, concentrated brightening rams-Q-mt fills other requirements made in the paper industry. As organic solubility promoters are necessary for the production of liquid forms of active ingredient which, as a rule, reduce the afiinity to the obje'ctsto be brightened,

the blue-fluorescent active ingredient employed in the manufacture of fine papers must have a good afiinity at least to some components of these carriers. A good affinity to the barium sulfate type and other white pigments is important for filled fine papers and, particularly, for coated fine papers.

The present invention is concerned primarily with active substances which are not only suitable for use in preparations in concentrated liquid form and are stable in the same even during long storage times, but which also have good affinity to the aluminum sulfate and barium sulfate type additives and other white pigments conventionally used in fine papers.

The active brightening agents contained in such preparations according to the invention fall under the formula X N N X \l S0311 SOaH l/ N N Rz R:

In this formula X represents advantageously hydrogen, or the methyl R represents a low molecular aliphatic radical containing at least one free hydroxyl group, advantageously a fl-hydroxy-ethyl group,

R represents a lower molecular alkyl radical, advantageously the methyl group. l i

A first aspect according to the invention concerns compositions containing valuable brightening agents which correspond to the formula L N N X N NHCH=CH-NH is X R1 TN l l NT R1 SOaH SOaH R, R: (II) fine papers the appearance of which is to be improved wherein by means of blue-fluorescent brightening agents.

Nowadays, agents, the blue fluorescence of which is more of a violet shade (which appears usually pinkish to the observer) are preferred to those of a blue fluorescence of greenish shade. v

A primary requirement of such industrial liquors containing active brightening ingredients is a high degree of stability even during prolonged storage.

Moreover, not every brightening ingredient which can be converted into a stable concentrated, liquid form ful- X represents a member selected from the group consisting of H and -CH v R represents a member selected from the group consisting of -CH2CH2OH, and

and I R represents a lower alkyl radical.

' Patented Dec. 26, 196'] Of these compounds, again those are preferred in which X is hydrogen and R is an alkyl radical containing at most 4 carbon atoms.

The active ingredients according to the first aspect of the invention, particularly those prepared with preferred components, have a clear to good afiinity to the additives in the making of fine papers, in particular to silicate fillers, such as china clay, talcum or kaolin, to aluminum sulfate and calcium sulfate additives, the so-called satin white, to calcium carbonate and barium sulfate (e.g. Blancofix), as well as to the binding agents usual in paper coating masses such as degraded starches, carboxymethyl celluloses and certain synthetic resin dispersions.

Concentrated, liquid forms of known brightening agent as Well as of those according to the invention and the active ingredients suitable therefor are obtained by (1) reacting in an aqueous medium in any order desired,

soluble salts of 1 mol of 4,4-diaminostilbene-2,2'-disulfonic acid and of 2 mols of an aminobenzene, with 2 mols of cyanuric halide and,

(2) in the resulting condensation product dispersed in the reacttion medium, reacting the remaining halogens with a lower molecular secondary alkanolamine, isolating the resulting product to separate the same as much as possible from inorganic salt (NaCl) and other byproducts of the reaction, and

HmS-Q-NH x N (3) subsequently admixing the product with water as well as certain organic solubility promoters which are easily soluble in water; and then, if necessary, filtering off solid precipitates from the concentrated solution of active ingredient.

- dialysis and the dilute solutions of the active ingredients are then concentrated by evaporating or steaming off the water.

Or, in lieu of using dialysis, the reaction product is isolated in the form of its free acid which can be washed with water to remove all electrolytes present therein. The free acid must then be converted to an alkali metal or an ammonium salt which is then used for preparation of stable, relatively concentrated solutions.

By adding organic solvents to the concentrated aqueous preparations of the end products so obtained, concentrated solutions of the active brightening ingredients are obtainedsometimes with further separation of precipitates formed, which solutions must be further clarified by filtering off such precipitates.

A particularly important, unexpected advantage of the brightening compounds according to the invention, and particularly according to the first aspect thereof, resides in the fact that they can be incorporated into liquid preparations in high concentrations, of 25% and higher,

mg. brightener stock solutions for industrial purposes, especially in the paper and textile industries, even when they still contain 10% or more of sodium chloride, due to the above described process of making them; such products consisting essentially of the brightening compounds defined above and 10% or more of sodium chloride are readily soluble in such industrial liquids and form no precipitates even when stored for long periods of time, of at least three to six months, or longer.

The content of inorganic salt of the sodium chloride type in the liquid brightening preparations according to the invention is maximally, calculated for the case of sodium chloride, about 10 to of the weight of the optical brightening agent, depending on the desired concentration of the latter in the preparation.

Known stilbene brighteners such as those described in US. Patent 3,012,971 to Gessner et al. require careful elimination of the salt content to a permissible amount of less than 5%, if industrial liquids with the abovearnentioned concentrations of brighteners are to be prepared. Otherwise, at sodium chloride contents of 5% and higher, precipitation of the brightener takes place, which may lead to spotty eifects on the treated materials.

A second aspect of the invention is concerned with optical brightening agent which are compounds of the formula (III) in which formula X represents methyl or, preferably, hydrogen,

R represents lower alkyl of from 2 to 4 carbon atoms substituted by from two to three hydroxyl groups, one of which is advantageously in fi-position to the respective amino nitrogen atom, not more than one hydroxyl group being linked to each carbon atom of R and R represents lower alkyl, preferably the methyl group.

The active ingredients according to this aspect of the invention, particularly those prepared with preferred components, also have a clear to good affinity to the additives in fine papers described hereinbefore.

Moreover, a particular advantage of the compounds according to this second aspect of the invention resides in the fact that their brightening activity does not suifer even in solutions with a relatively high content of alum and the like aluminum salts, as it occurs in the strong backwater (white water) of paper mills.

Hitherto known brighteners when introduced into such backwater, are usually precipitated in the form of their yellowish aluminum salt, and the result is an undesirable discoloration of the paper obtained from pulps processed with such backwater.

Highly concentrated aqueous preparations of the compounds (25% and higher) according to the second aspect of the invention, as they are used in industrial application for brightening purposes, are also stable for a much longer time even in the presence of inorganic salt (NaCl) in concentrations of about 10% and higher than are concentrated solutions of'known compounds pertaining to 7 the class of s-triazinyl-substituted stilbenes.

Optimal results are obtained with preferred brightening agents of this second aspect of the invention which correspond to the formula The reaction can be performed under otherwise comparable conditions in reversed order by first reacting the solution of the alkali metal salt of 1 mol of 4,4-diamino- X represents a member selected from the group consisting of hydrogen and methyl, R represents -CHzCHCH OH and R represents lower alkyl.

Of the compounds of Formula II those are preferred in which X is hydrogen and R is an alkyl radical containing at most 4 carbon atoms. I

The concentrated, liquid brightening preparations according to the invention and the active ingredients suitable therefor are obtained in the manner described hereinbefore, but with the following improvements:

(a) a soluble salt of 1 mol of 4,4'-diaminostilbene-2,2- disulfonic acid is reacted with 2 mols of a 4-aminophenyl sulfonic acid, the phenyl radical of which can be further substituted by a methyl group, and With 2 mols of cyanuric halide;

(b) the resulting intermediate condensation product is preferably isolated, e.g. by adding to the reaction medium inorganic salt (preferably NaCl) in amounts of about 5 to by weight calculated on the weight of the reaction medium, and again dispersed in water;

(c) the reaction of the remaining halogens is carried out with simultaneous or subsequent admixture of organic solubility promoters which are easily soluble in water, with a lower molecular secondary alkanolamine which contains an alkyl radical as nitrogen substituent.

(d) if no isolation of the intermediate condensation product has been effected, the final product is isolated by saturation of the reaction medium with inorganic salt (NaCl), about 30% being usually required.

Preferred brightening preparations and active ingredients suitable therefor according to the invention are obtained by using 4-aminobenzene-1-sulfonic acid.

More in detail, the reaction of 2 mols of an alkali metal salt of p-aminobenzene sulfonic acids is carried out in the cold with 2 mols of finely distributed cyanuric halide, in particular cyanuric chloride, at a pH of at most 7, and liberated acid is neutralized, for example, with dilute alkali carbonate or alkali bicarbonate solution, until the primary amino groups have disappeared. The the two mols of the alkali metal salt of 4-(4,6-dihalogen- 1,3,5-triazinyl-(2)-amino)-benzene-l-sulfonic acids are reacted at temperatures of from to 60 C. with the solution of 1 mol of an alkali metal salt of 4,4-diaminostilbene-2,2'-disulfonic acid until the free amino groups have disappeared, liberated acid being neutralized. Finally, the solution of the alkali metal salt of 4,4'-bis- [4 (4 sulfophenylamino) 6-halogen-1,3,S-triazinyl- (2)-amino]-stilbene-2,2-disulfonic acid obtained is reacted at elevated temperature (70 to 90 C.) with an excess of the secondary alkanolamine until the halogens bound at the triazine ring have all been replaced. This last reaction can be performed in the presence of an acidbinding nitrogen base.

halide, advantageously cyanuric chloride or, also, cyanuric bromide, until the primary amino groups have disappeared, then reacting the condensation product with the solution of the alkali metal salt of 2 mols of a 4- aminobenzene-l-sulfonic acid and, finally, with an excess of the above defined alkanolamine.

The moist intermediate condensation products separated in step (c), or the moist final products obtained in step (d), if precipitated as free acids in mineral acid solution, can be reacted with excess alkanolamine, in the presence of tertiary nitrogen base, whereby ammonium salts of the end product with these nitrogen bases are obtained.

These ammonium salts can also be used as active ingredients in the preparations according to the invention.

In the above described reaction, the necessary amount of solubility promoter depends to a great extent on its properties, but is considerably lower (e.g. less than half) than the amount of solubility promoter required in the known liquid high concentration brightening preparations. Such promoters are preferably liquid substances which are miscible with water; amounts of about 25 to calculated on the weight of the solid active ingredient according to the invention are sufiicient for the preparation of aqueous solutions having a content of active ingredient of 25-40%.

As organc solubility promoters which are easily soluble in water are used, for example:

Water miscible polyvalent alcohols such as ethylene glycol, propylene glycol, butylene glycol, glycerin, pentaerythritol, sugar, sulfite cellulose waste liquor; water miscible ether or thioether alcohols such as e.g., ethyleneglycol monomethyl, monoethyl, monopropyl or monobutyl ethers, di-fl-hydroxyethyl ether, di-B-hydroxyethyl-thioether, ethylene glycol di-fl-hydroxyethyl ether, diethylene glycol monomethyl or monoethyl ether, various not too high molecular polyglycol ethers;

Easily water soluble amides of carbonic acid or of carboxylic acids such as e.g., urea, N-dimethyl-methyl-, -ethyl-, -methoxyethylor ethoxyethyl-urethane, formamide, N-dimethyl-foramide, acetamide, N-diethyl acetamide, N-dimethylor N-diethyl-benzamide, acetic acid diethanolamide, benzoic acid diethanolamide; alkanolamines such as monethanolamine, diethanolamine, triethanolamine, N-methylor N-ethylmonoor -di-ethanolamines, propanolamines.

Instead of one of these compounds, it is often advantageous to use mixtures thereof. Ethylene glycol monomethyl and monoethyl ethers are preferred organic solubility promoters on the preparation of concentrated, liquid forms of brightening agents according to the invention.

Further details regarding the production and use of the active ingredients and liquid forms of brightening agents according to the invention can be seen from the following examples, which illustrate the invention without limiting it. Where not otherwise stated, parts are given therein as parts by weight. The temperatures are in degrees centigrade. The relationship of parts by weight to parts by volume is as that of grams to cubic centimeters.

7 8 EXAMPLE 1 HOOH2-CHQN SO Na SO Na. N-CHz-CHgOH CH CH If in this example the 126 parts of N-methyl mono- 148 parts of 4,4 -d1am1nest1lbene-2,2 -d1sulphon1c ac1d 10 are dissolved with 32 parts of sodium hydroxide in 2000 ethanolamine are replaced Parts of y m 8' parts of water. 290 parts of the sodium salt of 1-[2,4-diethanolamme then the fi Salt of b1sT[2 chloro-l',3',5-triazinyl (6) amino] benzene-4 suli h ,E P F P Q 4 f y i' Phonic acid are added While stirring at 40-50 within 1 1 3g 3 359 3 stilbene '1 g p i hour and the acid liberated is neutralised by successive adh 15 f f In an ana 5 S 3 ng F ditions of a solution of 43 parts of sodium carbonate in mg agent It IS an equally actwe Stable hquld Preparatlon' 250 parts of water. The whole-is then stirred at 5060 EXAMPLE 2 until after about 3 hours, no more free, primary, aromatically bound amino groups can be traced. 126 parts The aqueous suspension of the triazinyl compound of of N-methyl-monoethanolamine are then added to the the formula white suspension obtained which consists of the tetraobtained according to Example 1 from 4,4-diamin0stilsodium salt of 4,4'-bis [2-chloro-4" (p-sulphophenylbene-2,2-disulphonic acid and the sodium salt of 1-[2',4- amino)-1",3",5"-triazinyl-(6")-amino] stilbene-2,2'-didichloro-1',3',5-triazinyl-(6)-amino] benzene 4 sulsulphonic. acid, and the whole is heated for 1 /2 hours at phonic acid, is converted by salting outwith 10% sodium 85.90 while stirring. In this way, a yellowish to pale chloride into a form Which can easily be filtered. The brown coloured, clear solution is obtained which contains precipitate is filtered ofi under suction and dried in vacuo the desired triazinyl derivative of the formula given above. a 70"- An almost White, water soluble powder is ob- To convert it into a liquid preparation containing 37% tained as intermediate product. The active content is asof active substance, the solution is concentrated under re- C i d by d t rmining the amount of organically bound duced pressure to 960 parts and then converted into a relchlorine (total Chlorine less iOhOgenie n'ne). atively thinly liquid solution by heating with 240 parts of The amount of this intermediate product correspondethylene glycol monomethyl ether. Precipitated sodium ing to 205 parts is added to a solution of 75 parts of chloride is filtered off at 40 and the clear filtrate is made N-methylmoneethaflelamine in 0 p r s of Wa er and up t a weight f 1200 parts i h water, 120 parts of ethylene glycol monoethyl ether and the The sodium salt of 1-[2,4'-dichloro-1',3,5-triazinyl- Whole is heated for 4 hours at In this y, 3 (6')- i -b .4- l h i id mentioned above clear, stable preparation is obtained which contains the is produced as follows: 93 parts of cyanuric chloride are brightening agent described in Example 1 as active dissolved in 400 parts by volume of acetone and the solu- POIIeIIttion is poured While stirring into 1000 parts of ice water. If in this eXamPIe, The 75 Parts Of y meno- A solution of 97.5 parts of the sodium salt of sulphanilic ethanolamihe are replaced y 89 Parts of N-ethyl K10110- acid in 500 parts of water is poured within 30 minutes ethaholamine, then a Stable, liquid Preparation of the at 0 while stirring well into the fine cyanuric chloride Compound mentioned in the last Paragraph of Example 1 suspension so obtained and the acid liberated is neuis 8150 Obtainedtralised by the successive addition of 26.5 parts of sodium XAMPLE 3 carbonat Wh n I10 m e free Sulphahilic acid can he 37 parts of cyanuric chloride are dissolved in 200 arts traced, 150 part Of Sodium eh10r1de e added to the of acetone and the solution is poured while stirring into suspensl i Obialned, Whlte P F 1S filtered 0E, a mixture of 400 parts of crushed ice and 400 parts of washed with 5% sodium chloride solution and acetone waten A Solution f 37 parts f 44 di i tflb and drled 1n vaeu at 2,2'-disulphonic acid in 500 parts of 1.6% caustic soda The p h h Ohtalhed can he used 111 the usual h lye is poured Within 30 minutes While stirring into the r the whltelllng of ulose substrate. C mp e Wlth cyanuric chloride suspension obtained. The acid liberated Products In PllNeThlent form thls hquld Preparatlon has is neutralised by the successive addition of 16 8 parts of the advantage of being more Conveniently measured and sodium bicarbonate. As soon as no more free 44'-di- 9 belllg lTlhch more qlllekly' disturbed hh'mogehously aminostilbene-2,2'-disulphonic acid can be traced, 39 111 the y q when used In the P p Industry, the parts of the sodium salt of sulphanilic acid are added and Prepafahon h the f f Of a good affinlty to The the mixture is heated at 45-55 While keeping the ree usedhl P Pe i finlshhlg Such as 8 kaolin, China 7 action neutral with 15% aqueous sodium carbonate soluclay (aluminium silicate), talcum and calcium sulphate. tion until a sample tested by diazotisation shows that no In the production of fine papers such as e.g., chromo more free sulphanilic acid is present. In this way a papers, considerably more brightened results are obtained suspension of the tetrasodium salt of 4,4bis-[2"-chlo roon using the brightening preparation described than when 4" (p-sulphophenylamino) l",3",5 triazinyl-(6")- the usual paper brighteners are used. 5 amino]-stilbene-2,2'-disulphonic acid is obtained. This intermediate product can be isolated by the method described in Example 2 and it can be converted into the stable preparations described by reacting with N-methylor N-ethyl-monoethanolamine with the addition of ethylene glycol monoethyl ether.

Liquid preparations having an equally good action are obtained if the N-methyl monoethanolamine is replaced by equivalent amounts of the following bases: N-propyl monoethanolamine, N-butyl monoethanolarnine, N-rneth- If in this example, the 80 parts of ethylene glycol monoethyl ether used as solubility promoter are replaced by the same amount of the following glycol derivatives: ethylene glycol monomethyl ether, diethylene glycol, ethylene glycol-di-B-hydroxy-ethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, then stable, liquid brightening preparations containing about 30% of active substance are also obtained.

Similarly active brightening preparations are obtained Y isopfopanolamifle, Y P P -P PY if in this example, the 37.4 parts of 3-methyl-1-aminoisopropanolamine.

EXAMPLE 4 HO CHrCH2-N 37 parts of cyanuric chloride are dissolved in 200 parts by volume of acetone and the solution is suspended in a mixture of 500 parts of ice and 400 parts of water. The solution of 37.4 parts of 3-methyl-1-aminobenzene-4-sulphonic acid and 8 parts of sodium hydroxide in 300 parts of water is poured into the cyanuric chloride suspension so obtained while stirring and the acid liberated is neutralised by the successive addition of 10.6 parts of sodium carbonate. The almost white suspension is stirred at 0 until a diazotised sample shows that there is no more primary, aromatic amine present. 70 parts of sodium chloride are then added and the precipitated sodium salt of 2,4 dichloro 6 (3' methyl 4' sulphophenylamino)- 1,3,5-triazine is isolated by filtering oil? under suction. The product can be dried at room temperature in vacuo over sodium hydroxide or dehydrated calcium chloride, or it can be worked up direct in a moist condition.

37 parts of 4,4 diaminostilbene 2,2 disulphonic acid and 8 parts of sodium hydroxide are dissolved in 500 parts of water at 30-40. At this temperature, 72 parts of the sodium salt of 2,4 dichloro 6 (3' methyl 4'- sulphophenylamino)-1,3,5-triazine described above are added and the mixture is kept at a pH of 6-7 by the dropwise addition of aqueous sodium carbonate solution until no more 4,4'diaminostilbene-2,2-disulphonic acid can be traced. After adding 50 parts of sodium chloride, the pale grey suspension is quickly heated to 80, then cooled to and the tetrasodium salt of 4,4 bis [2'- chloro 4" (m methyl p sulphophenylamino)- S OgNB 1",3", 5" triazinyl (6") amino] stilbene 2,2 di- ITICH2CH2OH (3112 CZECH CH5 benzene-4-sulfonic acid are replaced by 37.4 parts of 2- methyl-l-aminobenzene-4-sulfonic acid.

EXAMPLE 5 S O 3N2. N-C Hr-CHnOH 148 parts of 4,4'-diaminostilbene-2,2'-disulphonic acid are dissolved with 32 parts of sodium hydroxide in 2000 parts of water. 290 parts of the sodium salt of l-[2',4'- dichloro 1,3,5' triazinyl (6) amino] benzene 4- sulphonic acid are added while stirrlng at 4050 within 1 hour and the acid liberated is neutralised by successive additions of a solution of 43 parts of sodium carbonate in 250 parts of water. The whole is then stirred at 50-60 until after about 3 hours, no more free, primary, aromatically bound amino groups can be traced. 200 parts of N- ethyl-l-aminopropane-2,3-diol are then added to the white suspension obtained which consists of the tetrasodium salt of 4,4 bis [2" chloro 4" (p-sulphophenylamino)- 1",3",5" triazinyl (6") amino] stilbene 2,2 disulphonic acid, and the whole is heated for minutes at 85-90 while stirring. In this way, a yellowish to pale brown coloured, clear solution is obtained which contains the desired triazinyl derivative of the formula given above.

To convert it into a liquid preparation containing 37% of active substance, the solution is concentrated under reduced pressure to 1000 parts and then converted into a relatively thinly liquid solution by heating with 240 parts of ethylene glycol monernethyl ether. Precipitated sodium chloride is filtered olf at 40 and the clear filtrate is made up to a weight of 1300 parts with water.

The sodium salt of 1-[2',4'-dichloro-1',3,5'-triazinyl- (6')-amino]-benzene-4-sulphonic acid mentioned above is produced as follows: 93 parts of cyanuric chloride are dissolved in 400 parts by volume of acetone and the solution is poured while stirring into 1000 parts of ice water. A solution of 97.5 parts of the sodium salt of sulphanilic acid in SOOI parts of water is poured within 30 minutes at 0 while stirring well into the fine cyanuric chloride suspension so obtained and the acid liberated is neutralised by the successive addition of 26.5 parts of sodium carbonate. When no more free sulphanilic acid can be traced, parts of sodium chloride are added to the suspension obtained, the white product is filtered off, washed with 5% sodium chloride solution and acetone and dried in vacuo at 35-45 1 1 l 2 The preparation obtained can be used in the usual Way Liquid preparations having an equally good action are for the Whitening of cellulose substrata. Compared with obtained if the N-ethyl-1-amino-propane-2,3-diol is reproducts in pulverulent form, this liquid preparation has placed by equivalent amounts of the following bases: the advantage of being more conveniently measured and N-methyl-l-amino-propane-2,3-diol,N ethyl tris(hyof being much more quickly distributed homogenously in 5 droxymethyl)-aminomethane [prepared from tris-(hythe dye liquor. When used in the paper industry, the droxymethyl)-arninornethane and ethyl bromide)] and preparation has the advantage of a good afiinity to the N-butyl-l-aminopropane-2,3-diol.

fillers used in paper finishing such as e.g. kaolin, china clay (aluminum silicate), talcum and calcium sulfate. In EXAMPLE 7 a (IJHB \N l l nooHcniN l sotNa SOaNa N-CH2CHOH 0112011 CH2 CH1 OHtOH CH CH the production of fine papers such as, e.g. chromo papers, 37 parts of cyanuric chloride are dissolved in 200 parts considerably more brightened results are obtained on by volume of acetone and the solution is suspended in 21 using the brightening preparation described than when mixture of 500 parts of ice and 400 parts of Water. The the usual paper brighteners are used. solution of 37.4 parts of 3-methyl-l-aminobenzene-4-sul- If in this example, the 200 parts of N-ethyl-l-aminophonic acid and 8 parts of sodium hydroxide in 300 parts propane-2,3-diol are replaced by 250 parts of N-butyl-1- 25 of water is poured into the cyanuric chloride suspension aminopropane-Zfi-diol, then the tetrasodium salt of 4,4'- so obtained while stirring and the acid liberated is neutra bis [2"-N-butyl-,B,'y-dihydroxy-propylamino-4"-(p-sulfolised by the successive addition of 10.6 parts of sodium phenylamino) 1,3",5"-triaZinyl-(6")-amino]-stilbenecarbonate. The almost white suspension is stirred at 0 2,2-disulfonic acid is obtained in an analogous manner. until a diazotised sample shows that there is no more As a brightening agent it is an equally active, stable, primary, aromatic amine present. 70 parts of sodium liquid preparation. chloride are then added and the precipitated sodium salt of 2,4-dichloro 6 (3' methyl-4-sulphophenylamino)- EXAMPLE 6 1,3,5-triazine is isolated by filtering off under suction. 37 parts of cyanuric chloride are dissolved in 200 parts The P d can fined at room temperature m vaFuo of acetone and the solution is poured while stirring into a SOdlum hy r xide or dehydrated calcium chloride, mixture of 400 parts of crushed ice and 400 parts of or It can be workefl 3 water. A solution of 37 parts of 4,4-diaminostilbene-2,2'- 37 Parts of 4,4 'dlammostllbene'lz dlsulphomc acld disulfonic acid in 500 parts of 1.6% caustic soda lye is and 8 Parts of Sodium hydroxide are dissolved in 500 PdttS poured within 30 minutes While stirring into the cyanuric of Water at this temperature, 7 Parts Of the chloride suspension obtained. The acid liberated is neu- Sodlum Salt of 'methyl'4 'sulphophenyl tralized by the sucessive addition of 16.8 parts of sodium e bed above are added and the bicarbonate. As soon as no more free 4,4-diaminostilbenemlxtul'e 1S kept at P 0t y the Q P f addltlOIl 2,2-disulfonic acid can be traced, 39 parts of the sodium of fl h Sodltlm ctThnate0h1t10n llhtll 110 more salt of sulfanilic acid are added and the mixture is heated 4,4"d1am1h0Stl1b6n6-2,2'-d1S111ph0111C id an e tracedat S5 while keeping the reaction neutral with 15% 45 After aftdlng 9 Parts of Sodlum Chloride, the P y aqueous sodium carbonate solution until a sample tested 51151361151011 q y heated Q 800, than C0016}1 t0 and by diazotisation shows that no more free sulfanilic acid is the tetfasodlum h of '-h t y present. In this way, a suspension of the tetrasodium salt p p y Y of 4,4'-bis-[2"-ch10r0-4"-(p sulfophenylamino)-1",3" 5- stilbene-2,2disulphonic acid obtained 15 filtered off. The triazinyl-(6")-amino]-stilbene-2,2'-disulfonic acid is obproduct is dried in vacuo at 70". 105.5 parts of the dried tained. intermediate product are added to a mixture of 90 parts This intermediate product is converted into an easily of ethylene glycol monoethyl ether; parts of N- y filtrable form by salting out with sodium chloride added -p p 3- 33 Parts trlethanolamme and in an amount of 10% by volume calculated on the total 140 Parts of Water and the Whole heated 9 2 hOIJIS volume of the reaction mixture, the precipitate is filtered at A Stable, P brown solutltfll 15 Obtained off under suction and dried in vacuo at 7() Th c i contains the product of the formula given above as active content is ascertained by analysis of the organically bound s e. chlorine (total chlorine less ionogenic chlorine). If in this example, the 90 parts of ethylene glycol An amount of the resulting dry crude, easily filtrable monoethyl ether used as solubility promoter are replaced intermediate product which contains 205 parts of the by the same amount of the following glycol derivatives: compound of the formula ethylene glycol derivatives: ethylene glycol monomethyl S O Na is added to a solution of 11.9 parts of N-ethyl-l-amino- 7 ether, diethylene glycol, ethylene glycol-di-fishydlroxypropane-2,3-diol in 25 parts of water and 15 parts of ethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and the whole is heated ethylene glycol monoethyl ether, then stable, liquid for 4 hours at 8090. A clear, stable preparation is o'bbrightening Preparations Containing about of active tained which contains the brightening agent described in substance are also obtained.

Example 1 as active component. Similarly active brightening preparations are obtained 13" if in this example, the 37.4 parts of 3-methyl-1-aminobenzene-4-sulfonic acid are replaced by 37.4 parts of 2- methyl-1-aminobenzene-4-sulfonic acid.

EXAMPLE 8 EXAMPLE 9 The procedure described in Example 1 is followed but the tetrasodium salt of 4,4'-bis-[2"-n-methyl-monoethanolamino 4" (p sulfophenylamino)-1",3",5"-triazinyl-(6")-amino]-stilbene-2,2-disulf0nic acid obtained is separated in a solid form by saturating with sodium chloride. It is dried in vacuo at 80; In this way, the brightening agent is obtained as a very easily Water soluble, pale yellow powder. To produce liquid preparations containing 30% of active ingredient, the substances listed in the following table in the given ratios can be used.

Brightening Solubility promoter agent (parts) 20 parts urea.

10 parts dimethyltormamide.

20 parts diethyltormamide.

15 parts diethylacetamide.

10 parts dimethylbenzamide.

20 parts diethanolamine.

20 parts triethanolamine.

15 parts monoethanolamine.

1O pziats sodium salt of m-xylene sulphonic 20 parts cane sugar.

10 parts peutaerythritol.

parts sulphite waste liquor+15 parts formamide.

20 parts glycerol.

20 parts propylene glycol-1,2.

20 parts ethylene glycol monopropyl et er.

parts ethylene glycol monomethyl ether. +t10 parts ethyleneglycol monobutyl et or.

10 parts urea+ 10 parts N-dimethylethylurethane.

20 parts dl-B-hydroxyethylthio ether.

20 parts N-dimethylmethoxyethylurethane.

20 parts acetamide.

20 parts acetic acid diethanolamlde.

20 parts benzoic acid diethanolamide:

Preparations with a higher content of active substance can be produced in an analogous manner. Thus, starting from the brightener mentioned above, the following combinations with 37.5% or even 40% content of active substance can be produced:

Water Brightening (pa t agent (parts) Solubility promoter 10 parts dimethyliormamide.

parts (llmethylt'ormamide.

15 parts monoethanolamine.

parts ethylene glycol.

20 parts 1,4-butane diol.

20 parts polyethylene glycol of molecular weight 400.

14 EXAMPLE 10 Potassium chloride is employed to salt out the potassium salt from the aqueous solution of the tetrasodium salt of 4,4'-bis-[2"-N-methyl-monoethanolamino-4"-(psulphophenylamino) 1,3",5"-triazinyl (6)-amino]- stilbene-Z,2'-disulphonic acid produced according to Example 1. The isolated potassium salt is dried and converted into a stable, liquid preparation by heating with ethylene glycol monoethyl ether and water in a ratio of 3:2:5. In this case, too, the solvent employed can be re placed by other hydrotropic substancessuch as e.g., dimethyl formamide or diethanolamine.

EXAMPLE 11 Dyeing in the paper mass of papers filled with white pigment An aqueous slurry containing 85 parts of cellulose, 15 parts of an aluminum silicate white pigment of the trade name China Clay and 0.15 part of a liquid brightening preparation obtained according to Example 1, is worked up in the usual way with 2 parts of resin size and 4 parts of aluminium sulphate into a paper sheet. A filled paper of very white appearance is obtained in this manner.

EXAMPLE 12 Surface coating of a chroma paper The following coating mass can be used, for example, to produce a chrome paper:

Parts China clay (aluminium silicate white pigment) 20 Satin white (calcium sulphate white pigment) 20 Synthetic resin dispersion of the trade name Acronal D 500 produced by Farbenfabriken Bayer, in Leverkusen, Western Germany 2 Casein 2 Water 5 6 Brightening preparation obtained according to Example 2 0.1

A considerably whiter paper is obtained with this coating mass than with the same coating mass which, however, contains a known marketed paper brightening agent.

EXAMPLE 13 Surface coating of a cutwork printing paper Paper intended to carry illustrations is coated in the usual manner with the following coating mass:

Parts China clay (aluminium silicate white pigment) 50 Degraded starch as binding agent 10 Water 40 Brightening agent obtained according to Example 1 A paper having an excellent white effect is obtained in this way.

What is claimed is:

1. A stable optical brightening aqueous composition consisting essentially of (a) the optical brightening agent having, in its free acid form, the formula Nrr-som E SOzH wherein X represents a member selected from the methyl-urethane, N-dimethyl-ethyl-urethane, N-digroup consisting of H and -CH R represents a methyl-methoxyethyl-urethane, N-di-methyl-ethoxymember selected from the group consisting of ethyl-urethane, formamide, N-dimethyl-formamide, CH CH OH and I acetamide, N-diethyl-acetamide, N-dimethyl-benza- 5 mide, N-diethyl-benzamide acetic acid diethanola- -OHZCHOH mide, mono-ethanolamine, diethanolamine, triethan- (3H3 olamine, N-methyl-mono-ethanolamine, N-methyldi-ethanolamine, N-ethyl-mono-ethanolarnine, N- and R2 represents lower alkyl and ethyl-di-ethanolarnine, propanolamine, the sodium (in) an organic solubility promoter selected from the 10 v Salt of III-Xylene Sulphonic acid and diethyl formgroup consisting of ethylene glycol propylene gly l amide, the solution having a content Of 25 t0 by butylene glycol, glycerin, pentaerythritol, sugar, sul- Weig of Said Optical brightening agent, and phite cellulose waste liquor, ethylene glycol monoq y of Said Organic Solubility Promoter being methyl ether, ethylene glycol monoethyl ether, ethylsufficient to maintain Said q y of Said Optical ene glycol monopropyl ether ethylene glycol mono- 15 brightening agent in solution in said preparation, but butyl ether, di-fl-hydroxyethyl ether, di-fi-hydroxynot substantially exceeding 100% of the weight of ethyl thioether, ethylene glycol, di-B-hydroxyethyl the brightening agent. ether, diethylene glycol monomethyl ether, diethyl- 2. A stable optical brightening aqueous composition ene glycol monoethyl ether, polyglycol ethers having as defined in claim 1, wherein the optical brightening agent a molecular weight of about 400, urea, N-dirnethyl- 20 is of the formula CH CH3 3. A stable optical brightening aqueous composition as defined in claim 1, wherein the optical brightening agent is of the formula 4. A stable optical brightening aqueous composition as defined in claim 1, wherein the optical brightening agent is of the formula 5. A stable optical brightening aqueous composition as defined in claim 1, wherein the optical brightening agent is of the formula CH3 CH2 OH: OH;

1 7 1 8 6. A stable optical brightening aqueous composition as defined in claim 1, wherein the optical brightening agent is of the formula References Cited UNITED STATES PATENTS 3,012,971 12/1961 Gessner et a1. 252--301.2 3,025,242 3/1962 Seylor 252-301.2 3,239,513 3/ 1966 Hausermann 252-3012 TOBIAS E. LEVOW, Primary Examiner.

R. D. EDMONDS, Assistant Examiner. 

1. A STABLE OPTICAL BRIGHTENING AQUEOUS COMPOSITION CONSISTING ESSENTIALLY OF (A) THE OPTICAL BRIGHTENING AGENT HAVING, IN ITS FREE ACID FORM, THE FORMULA 